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Abstract:

The present invention discloses a method for processing handover
capability and a base station, wherein the method includes: before the
Radio network Resource Control Re-establishment (RRC) is initiated in
User Equipment (UE), a target base station of a target cell of the UE
obtains Closed Subscriber Group (CSG) handover capability of the serving
cell from the serving base station; when the RRC connection is in
reestablishment, the target base station of the target cell processes the
RRC connection reestablishment according to the obtained CSG handover
capability. The present invention enables the behavior in UE and in the
network keep in alignment after the UE finishes RRC connection
reestablishment in the target cell while before it receives the first RRC
connection reconfiguration message which is transmitted by the target
cell.

Claims:

1. A method for processing handover capability, comprising: before the
Radio network Resource Control Re-establishment (RRC) is initiated in
User Equipment (UE), a target base station of a target cell of the UE
obtaining Closed Subscriber Group (CSG) handover capability of a serving
cell from a serving base station; and during the RRC connection
reestablishment, the target base station of the target cell processing
the RRC connection reestablishment according to the obtained CSG handover
capability.

2. The method for processing handover capability according to claim 1,
wherein, said CSG handover capability comprises one or more of the
following capabilities: whether to enable handover to a CSG cell, whether
to allow handover to a CSG cell, and whether to enable or allow the UE to
report proximity to a CSG cell.

3. The method for processing handover capability according to claim 1,
wherein, said step of a target base station of a target cell of the UE
obtaining CSG handover capability of a serving cell from a serving base
station comprises: said target base station of said target cell obtaining
CSG handover capability of a serving cell from the serving cell where the
UE camps before the UE initiates RRC connection reestablishment through a
handover preparation process, or a process of establishing an X2
interface between base stations, or a process of updating base station
configuration.

4. The method for processing handover capability according to claim 3,
wherein, said step of said target base station of said target cell
obtaining CSG handover capability of the serving cell through a handover
preparation process comprises: said target base station of said target
cell obtaining CSG handover capability of the serving cell from a
HANDOVER REQUEST message sent to the target base station from the serving
base station.

5. The method for processing handover capability according to claim 1,
wherein, said step of the target base station of the target cell
processing reestablishment of the RRC connection according to the
obtained CSG handover capability comprises: the target base station of
the target cell sending a RRC message to the UE according to the obtained
CSG handover capability so that the UE obtains CSG handover capability of
the target cell.

6. The method for processing handover capability according to claim 5,
wherein, said step of the target base station of the target cell sending
a RRC message to the UE according to the obtained CSG handover capability
comprises steps of: the target base station of the target cell judging
whether the CSG handover capability of the target cell is consistent with
the CSG handover capability of the serving cell; if consistent, the
target base station sending a RRC message to the UE, wherein the RRC
message does not carry the CSG handover capability of the target cell; or
if not consistent, then the target base station sending a RRC message to
the UE, wherein the RRC message carries the CSG handover capability of
the target cell.

7. The method for processing handover capability according to claim 6,
wherein, after the target base station of the target cell sends a RRC
message to the UE according to the obtained CSG handover capability, the
method further comprises: the UE processing handover capability according
to the RRC message after receiving the RRC message, comprising: the UE
parsing the RRC message; if the UE fails to obtain the CSG handover
capability of the target cell by parsing the RRC message, then
maintaining the stored CSG handover capability of the UE; or if the UE
obtains the CSG handover capability of the target cell by parsing the RRC
message, then updating the stored CSG handover capability according to
the CSG handover capability of the target cell.

8. A base station configured to: obtain Closed Subscriber Group (CSG)
handover capability of a serving cell from a serving base station of a
user equipment (UE); and to process Radio network Resource Control (RRC)
connection reestablishment according to the obtained CSG handover
capability when used as a target base station of a target cell of the UE
for performing reestablishment of RRC connection.

9. The base station according to claim 8, wherein said base station
comprises: a CSG handover capability obtaining unit configured to: obtain
CSG handover capability of a serving cell from the serving cell where the
UE camps before the UE initiates RRC connection reestablishment through a
handover preparation process, or a process of establishing an X2
interface between base stations, or a process of updating base station
configuration; and a first message sending unit configured to: send a RRC
message to the UE according to the obtained CSG handover capability after
the CSG handover capability obtaining unit obtains the CSG handover
capability of the serving cell so that the UE obtains the CSG handover
capability of the target cell.

10. The base station according to claim 9, wherein, said first message
sending unit is configured to: judge whether the CSG handover capability
of the target cell is consistent with the CSG handover capability of the
serving cell, if consistent, send a RRC message to the UE, wherein the
RRC message does not carry the CSG handover capability of the target
cell, and if not consistent, send a RRC message to the UE, wherein the
RRC message carries the CSG handover capability of the target cell.

Description:

TECHNICAL FIELD

[0001] The present invention relates to the field of mobile communication,
and in particular, to a method for handover capability processing and a
base station.

BACKGROUND ART

[0002] In the establishment of a radio network system, in-door covering
has become the most important part in the establishment of a network, a
suitable in-door covering scheme can, on one hand, enable the network
system to play its function to the utmost and create more values for the
operator, and on the other hand, can greatly reduce the costs of the
operator for establishing the network and actually achieve low investment
and high profits. Thus, a radio access device called Home (e)NodeB
emerges due to this demand. The Home (e)NodeB, as personal dedicated
equipment, is deployed in personal sites such as family, group, company
or school, and can provide the subscribers with various high-speed radio
access services with discounted charges, meanwhile it can compensate the
defect of deficient covering in the existing distributed macro radio
communication system.

[0003] The Home (e)NodeB, as personal dedicated equipment, is deployed in
special sites such as family, company or school, and the plurality of
cells covered by a Home (e)NodeB constitute the covering area of the Home
(e)NodeB. The cells covered by a macro base station (eNB) are called as
macro cells, and the cells covered by a Home (e)NodeB are called as Home
(e)NodeB cells. Currently the Home (e)NodeB includes three access modes:
open mode, closed mode and a hybrid mode, wherein a Home (e)NodeB of open
mode allows all subscribers to access, and the corresponding cells are
called as Home (e)NodeB cells of open mode (open cells); a Home (e)NodeB
of closed mode only allows authorized subscribers, for example authorized
family members, authorized group members and the like, to access, and
these authorized subscribers (member subscribers in short) constitute a
closed subscriber group (CSG), and the corresponding cells are called as
Home (e)NodeB cells of closed mode and are called as CSG cells in short;
a Home (e)NodeB of hybrid mode also has a closed subscriber group, it
does not only allow member subscribers to access, but also allows
non-member subscribers to access, but the member subscribers possess
preferential assurance for quality of service, preferential assignment of
resources and preferential right on charges, and the corresponding cells
are called as Home (e)NodeB cells of hybrid mode (hybrid cells).

[0004] After a UE (User Equipment) establishes a RRC (Radio Resource
Control) connection with a serving cell, the serving base station
indicates the UE, in the RRC Connection Reconfiguration message for
configuring radio resources for the UE, on whether the serving cell
enables handover to a CSG cell (CSG includes CSG/hybrid, which is called
as CSG handover capability in this application, and is called as
CSGinboundindication in short). After receiving this indication, UE
judges whether the serving cell enables handover to a CSG cell and stores
the CSG handover capability of the serving cell. When the UE enters the
proximity of a CSG cell the UE camped, and the frequency of this CSG cell
is denoted as f, if the serving cell enables handover to a CSG cell and,
the UE judges that the measurement configuration of the frequency f has
not been received from the serving base station yet, the UE can send to
the serving base station a message (this message may be a RRC Connection
Reconfiguration Request or a measurement report, which are called as
message 1 collectively in this application) with the frequency f of CSG
cell included. After receiving the message, the serving base station
judges that the UE may have approached a CSG/hybrid cell which has been
accessed before, and the serving base station can configure measurement
configuration (included in measurement configuration information of the
RRC Connection Reconfiguration message) on the frequency f for the UE.
The UE receives this measurement configuration, performs measurement in
accordance with this measurement configuration, evaluates the measurement
result and reports to the serving cell the CSG/hybrid cells that meet the
reporting conditions configured in the measurement configuration.

[0005] After receiving the CSGinboundindication in the RRC Connection
Reconfiguration message, UE stores the indication, and before a new RRC
Connection Reconfiguration message is received, the UE defaults that the
capability of handover to a CSG cell of the serving cell does not change.

SUMMARY OF THE INVENTION

[0006] In the process of the UE measuring the CSG/hybrid cell according to
the CSGinboundindication as described above, there are the following
problems:

[0007] When the UE initiates RRC connection reestablishment, the UE will
selects a suitable target cell for reestablishment at first. The target
cell may be the original cell, i.e., the cell where the UE camped before
performing reestablishment of RRC connection, or may be other cells
different from the original cell. And then the UE reestablishes RRC
connection on the target cell. In a case where the RRC connection is
reestablished on other cells, since the UE defaults the
CSGinboundindication to be not changeable, while the CSG handover
capability of the target cell may be just different from that of the
original cell, the UE may not act in accordance with the network after it
finishes RRC connection reestablishment but before it receives the first
RRC connection reconfiguration message from the target cell. For example,
the UE believes that the target cell enables CSG handover according to
the original CSGinboundindication and thus sends a message 1 to the
target cell, but in fact the target cell does not enables CSG handover
and cannot respond to the message 1 of the UE; or, UE thinks that the
target cell does not enables CSG handover according to the original
CSGinboundindication, but in fact the target cell enables CSG handover,
so even if the UE has entered the proximity of a CSG/hybrid cell which it
has accessed before, it will not send a message 1 to the target cell,
leading to the result that the UE cannot access the corresponding
CSG/hybrid cell after the UE reestablishes to the target cell, thus
affecting the subscriber's service experience.

[0008] The present invention provides a method for handover capability
processing and a base station, and solves the problem that the UE can not
access CSG cells after the RRC connection reestablishment.

[0009] In order to solve the above technical problem, the present
invention provides a method for handover capability processing,
comprising:

[0010] before the Radio network Resource Control Re-establishment (RRC) is
initiated in User Equipment (UE), a target base station of a target cell
of the UE obtaining Closed Subscriber Group (CSG) handover capability of
the serving cell from the serving base station; and

[0011] during the RRC connection reestablishment, the target base station
of the target cell processing the RRC connection reestablishment
according to the obtained CSG handover capability.

[0012] Preferably, said CSG handover capability comprises one or more of
the following capabilities:

[0013] whether to enable handover to a CSG cell, whether to allow handover
to a CSG cell, and whether to enable or allow the UE to report proximity
to a CSG cell.

[0014] Preferably, said step of a target base station of a target cell of
the UE obtaining CSG handover capability of the serving cell from the
serving base station comprises:

[0015] said target base station of said target cell obtaining CSG handover
capability of the serving cell from the serving cell where the UE camps
before the UE initiates RRC connection reestablishment through a handover
preparation process, or a process of establishing an X2 interface between
base stations, or a process of updating base station configuration.

[0016] Preferably, said step of said target base station of said target
cell obtaining CSG handover capability of the serving cell through a
handover preparation process comprises:

[0017] said target base station of said target cell obtaining CSG handover
capability of the serving cell from a HANDOVER REQUEST message sent to
the target base station from the serving base station.

[0018] Preferably, said step of the target base station of the target cell
processing reestablishment of the RRC connection according to the
obtained CSG handover capability comprises:

[0019] the target base station of the target cell sending a RRC message to
the UE according to the obtained CSG handover capability so that the UE
obtains CSG handover capability of the target cell.

[0020] Preferably, said step of the target base station of the target cell
sending a RRC message to the UE according to the obtained CSG handover
capability comprises steps of:

[0021] the target base station of the target cell judging whether the CSG
handover capability of the target cell is consistent with the CSG
handover capability of the serving cell;

[0022] if consistent, then the target base station sending a RRC message
to the UE, wherein the RRC message does not carry the CSG handover
capability of the target cell; or

[0023] if not consistent, then the target base station sending a RRC
message to the UE, wherein the RRC message carries the CSG handover
capability of the target cell.

[0024] Preferably, after the target base station of the target cell sends
a RRC message to the UE according to the obtained CSG handover
capability, the method further comprises:

[0025] the UE processing handover capability according to the RRC message
after receiving the RRC message, comprising:

[0026] the UE parsing the RRC message;

[0027] if the UE fails to obtain the CSG handover capability of the target
cell by parsing the RRC message, then maintaining the stored CSG handover
capability in UE; or

[0028] if the UE obtains the CSG handover capability of the target cell by
parsing the RRC message, then updating the stored CSG handover capability
according to the CSG handover capability of the target cell.

[0029] In order to solve the above technical problem, the present
invention provides a base station configured to: obtain Closed Subscriber
Group (CSG) handover capability of the serving cell from the serving base
station of a user equipment (UE); and to perform Radio network Resource
Control (RRC) connection reestablishment according to the obtained CSG
handover capability when become a target base station of a target cell of
the UE performing RRC connection reestablishment.

[0030] Preferably, said base station comprises:

[0031] a CSG handover capability obtaining unit configured to: obtain CSG
handover capability of the serving cell from the serving cell where the
UE camps before the UE initiates RRC connection reestablishment through a
handover preparation process, or a process of establishing an X2
interface between base stations, or a process of updating base station
configuration; and

[0032] a first message sending unit configured to: send a RRC message to
the UE according to the obtained CSG handover capability after the CSG
handover capability obtaining unit obtains the CSG handover capability of
the serving cell so that the UE obtains the CSG handover capability of
the target cell.

[0033] Preferably, said first message sending unit is configured to: judge
whether the CSG handover capability of the target cell is consistent with
the CSG handover capability of the serving cell, if consistent, send a
RRC message to the UE, wherein the RRC message does not carry the CSG
handover capability of the target cell, and if not consistent, send a RRC
message to the UE, wherein the RRC message carries the CSG handover
capability of the target cell.

[0034] The examples of the present invention provide a method for handover
capability processing and a base station, which enable the behavior in UE
and in the network keep in alignment after the UE finishes RRC connection
reestablishment in the target cell while before it receives the first RRC
connection reconfiguration message which is transmitted by the target
cell, i.e., the UE can process measurement and reporting of the
CSG/hybrid cell according to the CSG handover capability of the target
cell or the policy appointed in advance by the UE and the network
(predetermined policy) after the UE finishes RRC connection
reestablishment while before the UE receives the first RRC connection
reconfiguration message which is transmitted by the target cell to the
UE.

BRIEF DESCRIPTION OF DRAWINGS

[0035] FIG. 1 illustrates the covering scopes of the Home (e)NodeB and the
macro base station;

[0044] FIG. 10 illustrates the structure of the system for processing
handover capability provided in the examples of the present invention.

PREFERRED EMBODIMENTS OF THE INVENTION

[0045] The Home (e)NodeB, as personal dedicated equipment, is deployed in
special sites such as family, company or school, and the plurality of
cells covered by a Home (e)NodeB constitute the covering areas of the
Home (e)NodeB. The cells covered by a macro base station are called as
macro cells, and the cells covered by a Home (e)NodeB are called as Home
(e)NodeB cells. Currently the Home (e)NodeB includes three access modes:
open mode, closed mode and a hybrid mode.

[0046] A CSG cell only allows member subscribers to access, and a hybrid
cell is just a CSG cell for member subscribers, but for non-member
subscribers, it is a normal cell similar to a macro cell. If a member
subscriber of a CSG/hybrid cell in idle status has ever accessed a
certain CSG/hybrid cell which allows access through manual CSG cell
search or automatic CSG cell selection or reselection, the UE can store
the related information of the CSG/hybrid cell, including one of more of
the group consisting of PLMN (Public Land Mobile Network), frequency
information, PCI (Physical Cell Identity), CGI (Cell Global Identifier),
and TAC (Tracking Area Code) of the CSG/hybrid cell, and information
representing the location of the CSG/hybrid cell, for example, the
information of the neighbouring macro cell of the CSG/hybrid cell, or
GNSS (global navigational satellite system) location information of the
CSG/hybrid cell, and the like, and this information is called as the
fingerprint of the CSG/hybrid cell in this invention for a patent.
Afterwards, the UE can start to search/measure the CSG cell only when it
is judged according to the fingerprint of the CSG/hybrid cell that has
been stored that the UE has entered the proximity of the CSG cell.

[0047] In a long-term evolution (LTE) system, in order to ensure good
quality of service in a connected state and provide the subscriber with
good service experience, the UE needs to receive the measurement
configuration of the macro cell, perform measurement on
intra-frequency/inter-frequency/inter-RAT frequency neighbouring macro
cells, and report to the serving cell the neighbouring macro cells that
meet the reporting conditions configured in the measurement
configuration. The serving cell makes a handover decision according to
the measurement report of the UE and the related radio resource
management (RRM) algorithm. The macro network deployments are all
configured statically by the operator, so in the existing LTE-related
techniques, in order to implement interference coordination and ensure
that the UE camps on the best cell of the serving frequency, the serving
cell will configure intra-frequency measurement and the UE can always
perform intra-frequency measurement; but as for inter-frequency and
inter-system measurements, the serving cell generally configures
inter-frequency and inter-system measurements for the UE only when
receiving the report of the UE that the signal strength of the serving
cell is less than a configured threshold.

[0048] A Home (e)NodeB is a plug-and-play device and will probably be
deployed in a large number in the future, and the operator cannot
statically configure Home (e)NodeBs. A Home (e)NodeB may be deployed at
any place covered by a macro cell, as show in FIG. 1, the frequency of
the Home (e)NodeB 101 (f1). The frequency of the Home (e)NodeB 102 (f2)
are two inter-frequencies compared to the frequency of the macro base
station 103 (f0), the base station of the serving cell the UE currently
camps. When the UE approaches the Home (e)NodeB 102, the UE is far away
from the macro base station 103 at this moment, i.e., the signal strength
of the serving cell is less than the configured threshold, so the
technique for configuring inter-frequency measurement in the existing
LTE-related technology is applicable; but when the UE approaches the Home
(e)NodeB 101, the UE is very close to the macro base station 103 at this
moment, the signal strength of the serving cell is far more better than
the above configured threshold, so the serving base station will not
configure measurement on f1 for the UE according to the existing
LTE-related technology, causing the UE to be unable to measure or report
the CSG/hybrid cell on f1, and finally causing the UE to be unable to
handover to the Home (e)NodeB.

[0049] In order to solve the above problem, improvement is made on
measurement of CSG/hybrid in the prior art, i.e., after the UE
establishes RRC connection in the serving cell, the serving base station
indicates UE, in a RRC Connection Reconfiguration message for configuring
radio resources for the UE, on whether the serving cell enables handover
to a CSG cell (or an indication on whether the serving cell allows
handover to a CSG cell, or an indication on whether the serving cell
enables/allows the UE to report proximity to a Home (e)NodeB cell, which
is called as CSG handover capability collectively in this application for
the purpose of convenient description, and is called as
CSGinboundindication in short. Herein the CSG includes CSG/hybrid),
Receiving the indication, the UE judges whether the serving cell enables
handover to a CSG cell and stores the CSG handover capability of the
serving cell, for example, if the serving cell enables handover to a CSG
cell, the UE stores CSGinboundindication locally, and configures
CSGinboundindication to be TRUE. Based on the stored fingerprint
information, when the UE judges that it enters the proximity of a CSG
cell the UE camped, the frequency of which is denoted as f, if the
serving cell enables handover to a CSG cell and the UE judges that the
measurement configuration of the frequency f has not been received from
the serving base station yet, then the UE may send to the serving base
station a message (this message may be a RRC Connection Reconfiguration
Request or a measurement report, and is called as message 1 collectively
in this application) with the frequency f included. After receiving the
message, the serving base station judges that the UE may have approached
a CSG/hybrid cell which has been accessed before, and the serving base
station can configure measurement configuration on the frequency f for
the UE. The UE receives this measurement configuration, performs
measurement in accordance with this measurement configuration, evaluates
the measurement result and reports to the serving cell the CSG/hybrid
cells that meet the reporting conditions configured in the measurement
configuration.

[0050] The serving base station can configure measurement configuration on
inter-frequency or inter-RAT frequency for the UE according to the
message 1 sent by the UE timely, thereby ensuring good mobility of the UE
between a macro cell and an inter-frequency or inter-RAT Home (e)NodeB,
and meanwhile avoiding blind inter-frequency or inter-RAT measurement
configured for the UE.

[0051] After the UE receives the CSGinboundindication in a RRC connection
reconfiguration message, it stores the indication, and before a new RRC
Connection Reconfiguration message is received, the UE defaults that the
capability of whether enabling handover to a CSG cell of the serving cell
does not change. In the current LTE-related technology, when the UE
detects reasons such as radio link failure, handover failure, integrity
protection failure in L2, RRC connection reconfiguration message failure,
in order to ensure continuity of the service, the UE will initiate RRC
connection reestablishment, i.e., the UE firstly selects a suitable
target cell for reestablishment, which may be the original cell, i.e.,
the cell where the UE camps before performing RRC connection
reestablishment, or may be other cells different from the original cell,
and then reestablishes RRC connection on the target cell. In a case where
the RRC connection is reestablished on other cells, since the UE defaults
the CSGinboundindication to be not changeable, and the CSG handover
capability of the target cell may be just different from that of the
original cell, the UE may not act in accordance with the network after
the UE finishes RRC connection reestablishment while before the UE
receives the first RRC connection reconfiguration message which is
transmitted by the target cell to the UE.

[0052] For example, the UE thinks that the target cell enables CSG
handover in accordance with the original CSGinboundindication and thus
sends a message 1 to the target cell, but in fact the target cell does
not enable CSG handover and cannot respond to the message 1 of the UE. On
the contrary, if the UE thinks that the target cell does not enable CSG
handover in accordance with the original CSGinboundindication, but in
fact the target cell enables CSG handover, then even if the UE has
approached a CSG/hybrid cell which it has accessed before, it will not
send a message 1 to the target cell, leading to the result that the UE
cannot handover to the corresponding CSG cell, thus affecting the
subscriber's service experience.

[0053] In order to solve the above problem, the present invention provides
a method for handover capability processing. The network architecture of
a LTE system will be described firstly to introduce the method for
handover capability processing better.

[0054] In a LTE system, the premise for success of RRC connection
reestablishment is that a target cell must be a prepared cell, i.e., the
target cell has available UE context, which includes security capability
of the current UE, AS security information, E-RAB (E-UTRAN Radio Access
Bearer) information established for UE, information related with RRC
connection management (RRC context) and the like. In the process of RRC
connection reestablishment, the target cell distributes radio resources
for the UE directly according to the available UE context.

[0055] The network architecture of the LTE system is as shown in FIG. 2,
including an E-RAN (Evolved Radio Access Network) which is constructed
with an evolved base stations 201 (eNB), and an evolved packet core
network, wherein the evolved packet core network is composed of a MME
(Mobile Management Entity)/S-GW (Serving Gateway) 202. The interface
between eNB201 and the core network is S1 interface, wherein, the
interface between eNB201 and MME202 is indicated as S1-MME, which is used
for implementing mobility management and control panel function of the S1
interface; the interface between eNB201 and S-GW202 is indicated as S1-U,
which is used for implementing functions such as routing and delivery of
subscriber data. eNBs are connected with each other via an X2 interface,
which is used for implementing mobility management function when the user
equipment is in an active state and for information interaction between
equivalent eNBs.

[0056] In various examples of the present invention, the UE switches from
the serving cell to the target cell (the target cell including macro
cells and CSG or hybrid cells) when RRC connection is reestablished,
wherein the serving cell is located under a serving base station, the
target cell is located under a target base station, or both the serving
cell and the target cell are located under the same base station.

[0057] The Example one of the present invention will be further introduced
with reference to the attached drawings.

[0058] This example of the present invention will be described by taking
the process of handover preparation of an X2 interface as an example.

[0059] In the example of the present invention, firstly the target cell
obtains the CSG handover capability of the serving cell, the process of
which is as shown in FIG. 3, comprising:

[0060] Step 301, the serving base station sending a HANDOVER REQUEST
message to the target base station, wherein the message carries not only
the UE context in the serving cell existing in the prior art, but also
the CSG handover capability of the serving cell;

[0061] Step 302, after receiving the HANDOVER REQUEST from the serving
base station, the target base station storing the UE context in the
HANDOVER REQUEST, and judging whether the HANDOVER REQUEST can be
accepted, i.e., whether the resources required by the HANDOVER REQUEST
can be distributed to the UE, if can, then distributing resources to the
UE and returning a HANDOVER REQUEST ACKNOWLEDGE to the serving base
station, the message carrying not only E-RAB (E-UTRAN Radio Access
Bearer) information existing in the prior art and information of
resources distributed by the target base station for the UE, but also the
CSG handover capability of the target cell; if can not, then executing
step 303.

[0062] Step 303, the target base station returning a HANDOVER PREPARATION
FAILURE to the serving base station, wherein the message carries not only
the existing failure reasons, but also the CSG handover capability of the
target cell.

[0063] If there is no X2 interface between the serving base station and
the target base station, the target cell can also obtain the CSG handover
capability of the serving cell through a process of handover preparation
through S1 interface, i.e., the CSG handover capability of the serving
cell is carried in a HANDOVER REQUIRED, and the CSG handover capability
of the target cell is carried in a HANDOVER COMMAND or a HANDOVER
PREPARATION FAILURE.

[0064] In addition to the process of handover preparation, the target base
station can also obtains the CSG handover capability of the serving cell
through a process of configuration between the serving base station and
the target base station, for example, the target base station and the
serving base station can obtain the CSG handover capability of each cell
in adjacent base stations by carrying the capability of each cell under
the base station on whether to enable CSG handover in an X2 SETUP REQUEST
or an X2 SETUP RESPONSE in the process of setup of an X2 interface, or an
ENB CONFIGURATION UPDATE or ENB CONFIGURATION UPDATE ACKNOWLEDGE of the
X2 interface.

[0065] It should be pointed out that the examples of the present invention
are only described by taking a case as an example, in this case, the
target base station obtains the CSG handover capability of the serving
cell where the UE currently camps, and actually for a base station, it
can also obtain the CSG handover capability of all cells in its
neighbouring base stations through the above procedure.

[0066] The UE is currently acquiring service transmission in the serving
cell, the serving cell enables the capability of handover to a CSG cell,
the UE has acquired that the serving cell enables handover to a CSG cell
through a RRC connection reconfiguration message and has stored the CSG
handover capability indication of the serving cell, for example, the UE
has configured CSGinboundindication to be TRUE.

[0067] When the UE initiates RRC connection reestablishment due to reasons
such as radio link failure, or handover failure, or integrity protection
failure in L2, or RRC connection reconfiguration failure, the target base
station of the target cell can process RRC connection reestablishment
according to the obtained CSG handover capability.

[0068] Specifically, the target base station of the target cell sends a
RRC message to the UE according to the obtained CSG handover capability
of the serving cell, and the UE can update the local CSG handover
capability according to the CSG handover capability of the target cell
configured in RRC message sent by the target base station to the UE. In
the examples of the present invention, the RRC connection reestablishment
message is taken as the RRC message, and the flow is as shown in FIG. 4,
comprising:

[0069] Step 401, the UE selecting a target cell for RRC connection
reestablishment, and sending a RRCConnectionReestablishmentRequest to the
target base station;

[0070] In this step, the RRCConnectionReestablishmentRequest includes the
Cell Radio Network. Temporary Identifier (C-RNTI) of the UE in the
original cell (the serving cell), the PCI information of the original
cell, security configuration information of the UE in the original cell
(Short MAC-I) and the like.

[0071] Step 402, the target base station sending the RRC message to the UE
to inform the UE of the CSG handover capability of the target cell;

[0072] In the examples of the present invention, the RRC message sent by
the target base station to inform the UE of the CSG handover capability
of the target cell is specifically a RRC Connection Reestablishment
message.

[0073] In this step, after receiving the
RRCConnectionReestablishmentRequest sent by the UE, the target base
station queries the obtained UE context of the UE in the original cell
stored in the target base station according to the PCI of the original
cell, C-RNTI of the UE in the original cell, and Short MAC-I that are
carried in the RRCConnectionReestablishmentRequest, and reestablishes
Signal Radio Bearer 1 (SRB1) for the UE according to the UE context, and
sends it to the UE through the RRC Connection Reestablishment message.

[0074] When sending the RRC Connection Reestablishment message, the target
base station judges whether it needs to send CSGinboundindication in the
RRC Connection Reestablishment message according to the CSG handover
capability of the target cell, which specially comprises the following
two methods:

[0075] Method one, CSGinboundindication is sent in the RRC Connection
Reestablishment message according to the CSG handover capability of the
target cell, the CSGinboundindication can be carried in the RRC
Connection Reestablishment message only when the target cell enables
handover to the CSG cell to show that the target cell enables handover to
the CSG cell; or the CSGinboundindication can be carried in the RRC
Connection Reestablishment message regardless of whether the target cell
enables handover to the CSG cell or not, for example, when the
CSGinboundindication is configured to be TRUE, it is indicated that the
target cell enables handover to the CSG cell, and when the
CSGinboundindication is configured to be FALSE, it is indicated that the
target cell does not enable handover to the CSG cell.

[0076] Method two, whether to carry the CSGinboundindication in the RRC
Connection Reestablishment message is determined according to whether the
CSG handover capability of the target cell and the CSG handover
capability of the serving cell are consistent or not, for example, the
CSGinboundindication is not carried in the RRC Connection Reestablishment
message when the CSG handover capability of the target cell and the CSG
handover capability of the serving cell are consistent, and is carried in
the RRC Connection Reestablishment message when the CSG handover
capability of the target cell is not consistent with that of the serving
cell, thereby informing the UE of the CSG handover capability of the
target cell.

[0077] Step 403, the UE receiving the RRC Connection Reestablishment
message, and updating local indication of CSG handover capability
according to the RRC Connection Reestablishment message.

[0079] Corresponding to the two methods of the target base station
informing the UE of the CSG handover capability of the target cell by
sending the RRC Connection Reestablishment message as described in Step
402, the methods for the UE to update the indication of CSG handover
capability that is locally stored upon receiving the RRC Connection
Reestablishment message is as follows:

[0080] Method one, the UE parses the received RRC Connection
Reestablishment message, and corresponding to the Method one as described
in Step 402, if the target base station carries the CSGinboundindication
in the RRC Connection Reestablishment message only when the target cell
enables handover to the CSG cell, then the UE configures the local
CSGinboundindication to be TRUE upon getting a CSGinboundindication by
parsing the message, i.e., it is judged that the target cell enables
handover to the CSG cell; and configures the local CSGinboundindication
to be FALSE when it cannot get a CSGinboundindication by parsing the
message, i.e., it is judged that target cell does not enable handover to
the CSG cell. Or, if the target base station carries the
CSGinboundindication in the RRC Connection Reestablishment message
regardless of whether the target cell enables handover to the CSG cell or
not, then upon getting the CSGinboundindication, the UE updates the local
CSGinboundindication according to the indication, i.e., if the
CSGinboundindication in the RRC Connection Reestablishment message is
TRUE, then the UE configures the local CSGinboundindication to be TRUE
correspondingly; if the CSGinboundindication in the RRC Connection
Reestablishment message is FALSE, then the UE configures the local
CSGinboundindication to be FALSE correspondingly.

[0081] It should be pointed out that in a case where a UE enabling CSG
handover is reestablished to a target cell with lower-level version, as
the target base station where the target cell with lower-level version is
located cannot add CSGinboundindication to the RRC Connection
Reestablishment message, the UE deletes the locally stored
CSGinboundindication variable or configures the variable to be FALSE upon
receiving the RRC Connection Reestablishment message, at which moment,
the UE thinks that the reestablished target cell does not enable handover
to a CSG cell.

[0082] Method two, the UE parses the received RRC Connection
Reestablishment message, and corresponding to the Method two as described
in Step 402, upon getting a CSGinboundindication, the UE modifies the
locally stored CSGinboundindication if it judges that the CSG handover
capability of the reestablished target cell and that of the original
serving cell are not consistent, i.e., if the original
CSGinboundindication is TRUE, then it is modified to be FALSE, and if the
original CSGinboundindication is FALSE, then it is modified to be TRUE.

[0084] Example two will be introduced with reference to the attached
drawings.

[0085] The UE is currently implementing service transmission in the
serving cell, the serving cell does not enable handover to a CSG cell,
the UE has acquired that the serving cell dos not enable handover to a
CSG cell through a RRC connection reconfiguration message and has stored
the CSG handover capability indication of the serving cell, for example
the UE has configured CSGinboundindication to be FALSE.

[0086] When the UE initiates RRC connection reestablishment due to reasons
such as radio link failure, or handover failure, or integrity protection
failure, or RRC connection reconfiguration failure, if the UE defaults
that the CSG handover capability of the target cell does not change,
while the handover capability of the target cell is just the opposite,
this will lead to the result that the UE does not act in accordance with
the network after the UE finishes RRC connection reestablishment while
before the UE receives the first RRC connection reconfiguration message
(carrying the CSG handover capability of the target cell) which is
transmitted by the target cell. In order to solve the above problem, the
example of the present invention provides a method for handover
capability processing. In the example of the present invention, when
initiating RRC connection reestablishments, the UE processes the stored
CSG handover capability indication according to the policy appointed in
advance by the UE and the network (or a policy agreed in a protocol), as
shown in FIG. 5, comprising:

[0087] Step 501, the UE selecting a target cell for RRC connection
reestablishment, and the UE configuring the CSG handover capability of
the target cell to be enabling handover to a CSG cell as default before
sending a RRCConnectionReestablishmentRequest to the target cell;

[0088] In this step, before sending the
RRCConnectionReestablishmentRequest to the target cell, the UE firstly
configures the local CSGinboundindication to be TRUE (i.e., the UE
defaults that the target cell enables handover to a CSG cell) according
to the policy agreed by the UE and the network in advance.

[0089] Step 502, after the UE finishes RRC connection reestablishment in
the target cell while before the UE receives the first RRC connection
reconfiguration message transmitted by the target cell to the UE, the UE
detecting a CSG cell or a hybrid cell which has been accessed before, and
judging that the UE does not have the measurement configuration
information of the frequency of the CSG cell or the hybrid cell;

[0090] Step 503, the UE sending a message 1 to the target base station,
wherein the message 1 carries the frequency information (e.g., frequency
f) of the CSG cell or the hybrid cell;

[0091] In this step, the message 1 is specially a RRC connection
reconfiguration request or a measurement report.

[0092] Step 504, the target base station informing the UE of the CSG
handover capability of the target cell;

[0093] In this step, the target base station needs to judge whether the
policy agreed by the UE and the network in advance is consistent with the
CSG handover capability of the target cell, and configures measurement
configuration on the frequency f for the UE according to the judging
result or informs the UE of the CSG handover capability of the target
cell through a RRC connection reconfiguration message, which is specially
as follows:

[0094] if the target cell enables handover to a CSG cell, then the target
base station configures measurement configuration on the frequency f for
the UE, and the UE receives this measurement configuration and performs
measurement and measurement reporting according to the measurement
configuration; or

[0095] if the target cell does not enable handover to a CSG cell, then the
target base station sends to the UE a RRC connection reconfiguration
message which does not carry CSGinboundindication. After receiving this
message, UE configures the locally stored CSGinboundindication to be
FALSE, i.e., it is judged that the target cell does not enable handover
to a CSG cell.

[0096] It should be pointed out that in this example, the UE can also
firstly locally configures CSGinboundindication to be FALSE according to
the policy agreed by the UE and the network in advance or directly delete
the variable of CSGinboundindication before sending the
RRCConnectionReestablishmentRequest to the target cell, i.e., the UE
defaults that the target cell does not enable handover to a CSG cell
after the UE finishes RRC connection reestablishment and before the UE
receives the first RRC connection reconfiguration message transmitted by
the target cell, and then the UE sends a
RRCConnectionReestablishmentRequest to the target cell. Subsequently, the
UE waits for the target cell to send a RRC connection reconfiguration
message to inform the CSG handover capability of the target cell, as in
the prior art.

[0097] The example of the present invention further provides a UE having a
structure as shown in FIG. 6, comprising:

[0098] a first handover processing module 601 configured to receive a RRC
message sent by a target base station of a target cell and process
handover capability according to the RRC message; and

[0099] a second handover processing module 602 configured to process
handover capability according to a predetermined policy.

[0100] Wherein, the UE may only include the first handover processing
module 601, or only include the second handover processing module 602, or
include both.

[0101] Further, the structure of the first handover processing module 601
is as shown in FIG. 7, comprising:

[0102] an parsing unit 6011 configured to parse the RRC message; and

[0103] a handover capability processing unit 6012 configured to [0104]
maintain the local CSG handover capability when the CSG handover
capability of the target cell is not obtained through parse; or [0105]
update the local CSG handover capability according to the CSG handover
capability of the target cell when the CSG handover capability of the
target cell is obtained through parsing the RRC message; or [0106]
configure the local CSG handover capability to be not enabling handover
to a CSG cell when the UE fails to obtain the CSG handover capability of
the target cell through parsing the RRC message.

[0107] The example of the present invention further provides a base
station configured to: obtain CSG handover capability of a serving cell
from a serving base station of a UE; and to process RRC connection
reestablishment according to the obtained CSG handover capability when
used as a target base station of a target cell of the UE for performing
RRC connection reestablishment.

[0108] As shown in FIG. 8, the base station may comprise:

[0109] a RRC message sending module 801 configured to: send a RRC message
to the UE which implements RRC connection reestablishment in the target
cell, wherein the RRC message carries the CSG handover capability of the
target cell under the base station.

[0110] Further, the structure of the RRC message sending module 801 is as
shown in FIG. 9, comprising:

[0111] a CSG handover capability obtaining unit 8011 configured to: obtain
CSG handover capability of a serving cell from the serving cell where the
UE camps before the UE initiates RRC connection reestablishment, through
a handover preparation process, or through a process of establishing an
X2 interface between base stations, or through a process of updating base
station configuration; and

[0112] a first message sending unit 8012 configured to: send a RRC message
to the UE according to the obtained CSG handover capability after the CSG
handover capability obtaining unit obtains the CSG handover capability of
the serving cell, so that the UE obtains the CSG handover capability of
the target cell.

[0113] Specifically, the first message sending unit is configured to:
judge whether the CSG handover capability of the target cell is
consistent with the CSG handover capability of the serving cell, if
consistent, sends a RRC message to the UE, wherein the RRC message does
not carry the CSG handover capability of the target cell, and if not
consistent, then sends a RRC message to the UE, wherein the RRC message
carries the CSG handover capability of the target cell.

[0114] The RRC message sending module 801 may further comprise a second
message sending unit 8013 configured to: judge the CSG handover
capability of the target cell when the CSG handover capability obtaining
unit does not obtain the CSG handover capability of the target cell, and
send to the UE a RRC message carrying the CSG handover capability of the
target cell when the target cell enables handover to a CSG cell, wherein
the CSG handover capability is used to represent that the target cell
enables handover to a CSG cell; or send to the UE a RRC message carrying
the CSG handover capability of the target cell when the target cell does
not enable handover to a CSG cell, wherein the CSG handover capability is
used to represent that the target cell does not enable handover to a CSG
cell; or, send to the UE a RRC message not carrying the CSG handover
capability of the target cell when the target cell does not enable
handover to a CSG cell.

[0115] The example of the present invention further provides a system for
processing handover capability having a structure as shown in FIG. 10,
comprising a UE1001 and a target base station 1002, wherein the UE1001
implements RRC connection reestablishment in a target cell under the
target base station 1002;

[0116] The UE1001 is configured to receive a RRC message sent by the
target base station 1002 of the target cell, and process handover
capability according to the RRC message; or, process handover capability
according to a predetermined policy;

[0117] The target base station 1002 is configured to send a RRC message to
the UE1001, wherein the RRC message carries the CSG handover capability
of the target cell.

[0118] The above UE, base station and system for processing handover
capability may be combined with a method for processing handover
capability provided in the examples of the present invention, and when
the UE implements RRC connection reestablishment from a serving cell to a
target cell, the target base station of the target cell sends a RRC
message to the UE to inform the UE of the CSG handover capability of the
target cell, upon receiving the RRC message, the UE updates the local CSG
handover capability according to the CSG handover capability of the
target cell; or, when the UE implements RRC connection reestablishment
from a serving cell to a target cell, the UE processes the local CSG
handover capability according to a predetermined policy, thereby enabling
the UE to act in accordance with the network after the UE finishes RRC
connection reestablishment in the target cell and before the UE receives
the first RRC connection reconfiguration message which is transmitted by
the target cell to the UE, i.e., the UE can process measurement and
reporting of the CSG/hybrid cell according to the CSG handover capability
of the target cell or according to the policy appointed by the UE and the
network in advance (a predetermined policy) after the UE finishes RRC
connection reestablishment in the target cell and before the UE receives
the first RRC connection reconfiguration message which is transmitted by
the target cell to the UE.

[0119] A person skilled in the art should appreciate that all or part of
the steps for implementing the above method examples of the present
invention can be done by instructing related hardware with a program, and
the program may be stored in a computer readable storage medium, and the
program includes one of the steps of the method examples or combinations
thereof.

[0120] In addition, each functional unit of the each example of the
present invention may be realized in the form of hardware, or may be
realized in the form of a software functional module. The integrated
hardware can also be stored in a computer readable storage medium when
realized in the form of a software functional module and sold or used as
an independent product.

[0121] The storage medium mentioned above may be a read only memory, a
disk or a laser disk.

[0122] The above examples are only specific examples of the present
invention, but the protection scope of the present invention is not
limited thereto, all transformations or substitutions that can be readily
conceived by any person having ordinary skill in the art without
departing from the technical scope of the present invention shall be
within the protection scope of the present invention. Therefore, the
protection scope of the present invention is defined by the claims.

INDUSTRIAL APPLICABILITY

[0123] The present invention provides a method for processing handover
capability and a base station, which enable the behavior in UE and in the
network keep in alignment after the UE finishes RRC connection
reestablishment while before the UE receives the first RRC connection
reconfiguration message which is transmitted by the target cell to the
UE, i.e., the UE can process measurement and reporting of the CSG/hybrid
cell according to the CSG handover capability of the target cell or the
policy appointed in advance by the UE and the network (predetermined
policy) after the UE finishes RRC connection reestablishment and before
the UE receives the first RRC connection reconfiguration message which is
transmitted by the target cell to the UE.